During cardiac surgery for procedures such as coronary artery bypass grafting, heart valve repair or replacement, septal defect repair, pulmonary thrombectomy, atherectomy, aneurysm repair, aortic dissection repair and correction of congenital defects, cardiopulmonary bypass and cold cardiac ischemic arrest are often required. Typically, a cooled cardioplegia solution, a solution containing elevated levels of potassium, for example, is administered in the antegrade direction (in the direction of normal blood flow) through the patient's aorta and into the coronary arteries. The cold (2 to 3 degrees centigrade) cardioplegia solution stops the heart from beating and reduces its temperature to minimize damage to the heart during surgery. The cardioplegia solution exits the coronary circulation through the coronary veins at the coronary sinus, where it empties into the right atrium. Cardiopulmonary bypass maintains the peripheral circulation of oxygenated blood to all body organs except the heart during the period of cold, cardioplegic, ischemic arrest.
For some patients, such as those suffering from critical coronary artery stenosis and aortic valve disease, antegrade perfusion may be difficult, inefficient and incomplete. Retrograde (in the direction opposite of normal blood flow) cardioplegia, using current technology, may be administered via the coronary sinus into the coronary circulation using devices, which cannulate the coronary sinus. Such cannulation of the coronary sinus by prior art devices requires inserting a catheter into the coronary sinus and perfusing cardioplegia into the sinus. Drainage of cardioplegia solution is accomplished into the coronary ostea located at the base of the aorta. The problem with prior art methods is that either the right or left heart will be perfused, but not both, since the right coronary veins come off the coronary sinus at an angle and are not cannulated by current catheters that cannulate the left coronary veins. Thus, incomplete perfusion of segments of the heart muscle, primarily the right heart and septum, will occur since the right coronary veins frequently come off near the coronary sinus ostea or within the right atrial wall proper. The right coronary veins are not perfused by prior art retrograde cardioplegic catheters.
Currently surgeons performing cardiac bypass surgery use one or more cannulae for venous drainage and an additional cannula for retrograde perfusion. The multiple cannulae are obstacles and restrict visibility in the surgical arena. Placement of the cardioplegia cannula into the coronary sinus is a semi-blind procedure performed through an additional purse-string suture-closed access port via the right atrium. The retrograde cannula may be improperly positioned within the coronary sinus, which results in critical coronary vessels being inadequately perfused. Typically, placement of currently available retrograde cardioplegia cannula within the coronary sinus results in retrograde perfusion of the left heart but inadequate retrograde perfusion of the right heart because of cannula obstruction of the right coronary ostea as they arise from the coronary sinus. Thus the tissue of the left heart is perfused, in a retrograde direction, with cardioplegia solution but the right heart is perfused with a diminished, or no, supply of cardioplegia solution since the right coronary veins are generally a side-branch of the left coronary veins at the coronary sinus and the right coronary veins are blocked by the cannula. Poor right heart retrograde perfusion occurs because, most-frequently, anatomic variations of the right coronary sinus and veins cannot be properly perfused with the currently available cannula.
New devices and methods are needed, which facilitate cold cardioplegic arrest, yet limit the number of cannulae required to isolate the heart and coronary blood vessels from the peripheral vasculature, arrest the heart, protect all the coronary blood vessels, protect all or most of the myocardium, and drain venous blood from the inferior and superior vena cava. Furthermore, it would be advantageous to the diseased myocardium being subjected to ischemic arrest if a retrograde cardioplegia perfusion cannula could perfuse the coronary vasculature of both the right and left heart simultaneously.